In order to be able to produce a homogeneous transition between different thicknesses of a metal strip in the width direction, it is known from the prior art (WO2012119166A1) to permit at least one peripheral working roll or flat roller to penetrate into the metal strip across its strip width during the longitudinal rolling. In addition, before this roll pass, the rolling stock or metal strip is provided with grooves, which as an opening in the metal strip, encourage a flow of material in the width direction of the strip material and thus counteract a flow of material in its longitudinal direction. Nevertheless—particularly depending on the width of the flat roller—an uneven flow of material can occur in the longitudinal direction of the metal strip, which can result in rippling in the strip.
The intent of EP976462A2 is to avoid such rippling in the strip by using—instead of a flat roller—a plurality of profiled rollers that are staggered relative to one another in the width direction and situated one after another in the longitudinal direction, namely pressing rollers, which penetrate into the metal strip in some regions. Providing a plurality of rollers, however, requires an increased design and control expense—such multiple-roller designs are also generally sensitive to geometrical irregularities in the metal strip, which can reduce the reproducibility of the thickness profiling method.